Molding press for paste like material

ABSTRACT

A molding press is provided with a hopper for feeding a mixture into a chamber between a main piston in the press and an opposed piston slidably mounted in an insert which may be placed in the press. The insert piston presses the material against the main piston to form the bottom of a container and four transversely arranged pistons move into the chamber to press the material against the sides of the insert piston to form the four sides of the container. The main piston then ejects the formed container from the chamber into the insert and the insert is then removed from the press to allow the formed container to harden before removing the container from the insert.

United States Patent 1191 Boffet et al.

[ 1 Oct. 2, 1973 MOLDING PRESS FOR PASTE-LIKE MATERIAL [76] Inventors: Andre Bofiet; Pierre Buffet, both of La Bardiniere-Chauffailles (Saone et Loire), France 22 Filed: Mar. 16, 1971 211 Appl. No.: 124,694

[52] US. Cl 425/330, 425/354, 425/404,

425/455 [51] Int. Cl. B29c 3/04, B291: 7/00 [58] Field of Search 18/16 F, 16.5, 16 H,

Primary Examiner-Robert L. Spicer, .Ir. Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A molding press is provided with a hopper for feeding a mixture into a chamber between a main piston in the press and an opposed piston slidably mounted in an insert which may be placed in the press. The insert piston presses the material against the main piston to form the bottom of a container and four transversely arranged pistons move into the chamber to press the material against the sides of the insert piston to form the four sides of the container. The main piston then ejects the formed container from the chamber into the insert and the insert is then removed from the press to allow the formed container to harden before removing the container from the insert.

6 Claims, 12 Drawing Figures PATENTEU 2 3,762,852

SHEET 30F 5 MOLDING PRESS FOR PASTE-LIKE MATERIAL The present invention relates to a molding press for the fabrication of articles made from a material such as reconstituted wood, more particularly from a mixture containing a high percentage of defibered wood and a low percentage of binder.

Such a molding press is known, especially for making in one sole phase, and in a single piece, a packing box of the kind used for transporting fruits and vegetables, for example, a moulding press of this type is described in French Patent 1, 573,928.

A molding press of known type has the following drawbacks:

1. After compressing and forming the molded material, it was necessary to heat the mold for about 2 minutes for a sufficient hardening; then it was necessary to wait for nearly 2 minutes before ejecting the article out of the mold in order to realize another article, which limits the production ratio of the press.

2. The known techniques accomplish a transfer of material through small intervals in the mold, which is difficult to obtain for molding thin-walled articles, i.e., for forcing material into deep and thin spaces, it would be necessary to deliver an extremely large mechanical force which would result in excessive over dimensioning of the machine.

The present invention aims to avoid these drawbacks by providing a molding pressadapted to work automatically at a high speed for the fabrication of thin-walled articles such as boxes or packing boxes without any extremely large mechanical force.

A molding press according to the invention is of the same type as in French Patent 1, 573, 928 and is characterized by the fact that each removable insert is made of a rigid body within which is defined an impression corresponding to the periphery of the article to be molded while inside this body is slidably mounted a piston defining the inner face of the article side walls. The piston is controlled on its rear face by means of a ram when the removable insert is at its molding position on the press for defining the inner surface of the article bottom. The outer surface of said bottom is defined by one single piston sliding in the opposite direction under the feed hopper of the press, the molding operation being performed in a first phase by forwardly moving the insert piston against the stationary opposite piston for molding the bottom, whereafter the four lateral pistons are drawn around the insert piston for molding the side walls of the article. The latter is then transferred in a third phase into the removable insert by forwardly moving the bottom piston of the press and simultaneously rearwardly moving the insert piston.

It will be understood that this arrangement permits the agglomerated wood article to achieve its definitive shape before being entirely transferred by sliding into the removable insert. Thus, the molded material is never submitted to a sliding movement with friction and compression on both faces of any wall of the article; this permits a substantial reduction of the mechanical power necessary for operating the press.

According to another characteristic of the invention, each removable insert is provided with handling means so that, after molding, it is possible to carry it away from the press and to rotate it at 90 before putting it on an evacuation conveyer provided with a supporting face which has the same shape as the outer face of the article bottom, i.e., the same shape as the front face of the press transfer piston. Thus, the molded article is kept compressed by the weight of the insert as long as it rests on the evacuation conveyer. This avoids any decompression of the material before complete hardening; it permits the material to harden as long as necessary without slowing down the rhythm of fabrication of the molding press.

The annexed drawing, given by way of non-limitating example will permit better understanding of the characteristics of the invention.

FIG. 1 is a perspective view diagramatically showing the main molding members of the molding press.

FIGS. 2 to 6 are vertical sections along VI-Vl (FIG. 1) illustrating successive molding phases.

FIG. 7 is a top plan section along VIIVII (FIG. 6).

FIG. 8 is a front view in the direction of arrow VIII (FIG. 5) diagramatically showing the press without the insert piston.

FIG. 9 is a vertical section along IXIX (FIG. 1) showing an insert and the molded article both on the evacuation conveyer.

FIG. 10 is a section similar to FIG. 9 showing the insert body raised up for ejecting the molded article.

FIG. 11 is a section along XI--XI (FIG. 10).

FIG. 12 is a perspective view of a packing box obtained in a single piece by molding agglomerated wood in a press according to the invention.

The press illustrated in the drawings is specially designed for molding in a single piece, packing boxes 1 made from agglomerated wood in the shape shown in FIG. 12. Such a packing box has a bottom 2 located between longitudinal side walls 3 and transverse side walls 4. For reasons of rigidity, it is advantageous to give side walls 4 a corrugated shape making it possible to stack the boxes upon each other and to obtain a sufficient rigidity in spite of the thinness of the side walls.

Moreover, for facilitating handling a box on a stack of similar boxes, it is provided that the bottom 2 protrude between the corrugations of the side walls 4, thus forming stacking lugs or thrust walls 5 located all in the same plane and limited by a straight edge 6.

Finally, the longitudinal side walls 3 are each provided with an upper indentation 7, for sufficiently ventilating the box contents when a number of such packing boxes are stacked upon each other.

For molding a packing box 1 (FIG. 12), the present invention uses the press illustrated in FIGS. 1 to 11.

Said press comprises a feed hopper 8 receiving the mixture 9 to be compressed. Said mixture is made from defibered wood added with a low percentage of hard ening resins.

The feed hopper 8 opens at its lower end into a chamber 10 wherein the feed piston 13 is sliding in a longitudinal direction. Said piston 12 is used for rejecting the charge of mixture 9 from chamber 10 through an opening 13 provided in a vertical main wall 14, above a fixed frame 15 within which is sliding the main longitudinal piston 16. Said piston is moved by means of a double stroke jack in the direction of the arrow 17. Its front face 18 has a shape corresponding to the desired shape of the lower face of the bottom 2 of the packing box.

Around the piston 16 and on the front face of the main wall 14 are sliding two horizontal transverse pistons 19 and 20 (arrows 21 and 22) and two vertical transverse pistons 23 and 14 (arrows 25 and 26).

Both vertical transverse pistons 23 and 24 have a flat front face 27 or 28 (FIG. 2), while the from face 29 or 30 ofthe horizontal pistons 19 and 20 (FIGS. 7 and 8) is corrugated for following the outside profile of the side walls 4 of the packing box 1.

When those four transverse pistons 19, 20, 23, 24 are closed around the main piston 16 (FIGS. 6 and 7 and 8), they define around said piston 16 a space which is filled up with mixture 9 to form the side walls 3 and 4 of-the box 1.

For completing the mold, removable inserts A which are all identical are placed successively in front of the press.'In FIG. 1, reference numeral A corresponds to the insert placed in molding position, while reference numerals A,A A correspond to the insertsremoved from the press after molding. In FIGS. 9, 10 and 11, reference numeral A corresponds to the insert arriving at the ejection place.

Each insert A has a rigid body 31 with an inner cylindrical cavity, the periphery 32 of which is identical to the outer top plan periphery of the final packing box 1. In this impression 32 is mounted a fixed sleeve 33 extending along a portion only of the length of the body 31 and having a border 34 turned toward the piston 16 (FIGS. 2 and Said border 34 follows the profile of the upper edges of the box side walls 3 and 4 (FIG. 12), especially for defining the indentations 7.

Inside the fixed sleeve 33, the thickness of which is the same as the thickness of the side walls 3 and 4 of the box 1, is sliding a piston 34 with a chamber corresponding to the inner profile of the side walls 3 and 4 and of the'bottom 2 of the box 1. When the insert A is at its molding position (FIGS. 1 to 8), the piston 35 is opposite to the piston 16. Moreover, the insert A placed in molding position is brought before the driving rod 36 of a double acting jack which is mounted at a fixed place on the press for driving the piston 35 of the corresponding insert.

Each insert has on the sides of its body 31, handling trunnions 37 adapted to receive hoisting hooks 38. After molding, this permits to remove the insert A and to bring it into the position A where it is rotated at 90 around the trunnions 37. Finally, it is laid down onto the delivery conveyor 39. The latter delivers the inserts A A A etc. in the direction of the arrow 40.

The carrying face of the delivery conveyors 39 is provided with impressions, each corresponding to the lower face profile of the box bottom 2, just like the front face 18 of the piston 16 does.

Removable latches 40 are provided on the conveyor 39 for acting on the lugs 41 which protrude laterally from the body 31 of each insert A. Said latch cooperates with the proper weight of the body 31 and insert piston 35 for keeping the molded material of the box I compressed on the conveyor 39.

At the removing place, the latches 40 are turned aside (FIG. 10), then the insert body 31 is raised and the box 1 is retained on the conveyor 39 by the weight of the piston 35. Said piston 35 has indexes 42 sliding through openings 43 of the body 31. Said indexes 42 are working as stop members when they come at the height of the lower end of slots 43, so that when going on in raising the body 31, the piston 35 is also elevated (FIG. 11) and the inside of the box 1 is removed from the mold. Stops 44 provided at that time above the side walls 3 and 4 of the box I, retain the latter on the conveyor 39 and only the piston 35 is elevated.

The operation is as follows:

In a first stage, after pouring the charge of mixture 9 into the chamber 10 (FIG. 2), the piston 12 is moved fowardly (FIG. 3, arrow 1l) for obturating the bottom of the feed hopper 8 and for transferring the mixture 9 between the pistons l6, 19, 20, 23, 24, 35 which are away from each other.

Then, the piston 35 of the insert is moved toward the main piston 16 until compressing the material of the box bottom 2 to its definitive shape (FIG. 4). During this time, the side pistons 19, 20, 23, 24 are moved more slowly in the forward direction. At the end of the operation for compressing the bottom 2 (FIG. 4), said side pistons are for example, at the middle of their stroke. They have forced the mixture 9 around the protruding insert piston 35.

The side pistons 19, 20, 23, 24 are still advancing until they compress the mixture 9 around the piston 35 fordefining the side walls 3 and 4 of the box, the upper edges 45 of said side walls 3 and 4 still being raw.

At the following stage (FIG. 6) the side pistons 19, 20, 23, 24 remain stationary while the piston 16 is moved forwardly to push before it the box 1 and the piston 35 of the insert A,. The box 1 together with the piston 35 is penetrating into the fixed body 31 of the insert. At the end of the stroke, the movement of the piston 16 causes a modification in the shape of the box elements. As a matter of fact, the still plasticized matter is meeting with the edges of the sleeve 33, the profile of which gives their definitive shape to'the upper edges of the side walls 3 and 4, specially with respect to the indentations 7.

In the meantime, a new charge of mixture 9 has been poured into the hopper 8 and the molding press is ready for a ney cycle (FIGS. 1 and 2) by rearwardly moving the pistons 16, 19, 20, 23, 24.

It will be noted that the molded article 1 contained within the insert A, still does not have its definitive shape, at least with respect to a secondary detail: as a matter of fact, a wall 46 is protruding under the bottom 2 in alignment with the corrugated side walls 4 (FIGS. 5, 6 and 7).

The insert A, containing the molded box 1 is moved away from the press, then rotated at about the trunnions 37 and laid down at the place of the insert A, on the delivery conveyor 39 (FIG. 1.) During this rotation, the wall 46 is turned outwardly in alignment with the bottom 2, by the weight of the insert A, since the impression on the conveyor 39 has a profiled shape. This crushing of wall 46 forms the lugs or stacking stops 5 (FIGS. 9 and 12) on the box 1, which has now its definitive shape.

The latches 40 fix the insert on the conveyor 39 for keeping compressed the-matter of the box I as long as it is necessary for its solidification.

As above mentioned, when an insert A is coming at the removing place, the latches 40 are turned apart and it is sufficient to raise the trunnions 37 for removing the box 1 out of the mold, i.e., successively its outer face (elevation of the body 31, FIG. 10) and its inner face (elevation of the piston 35, FIG. I1.

After this operation, the conveyor 39 carries a final packing box I which can be directly delivered.

What is claimed is:

l. A molding press for the fabrication of agglomerated wood particles such as packing boxes for the transport of fruits and vegetables comprising a frame having a central molding chamber, feed means for feeding a molding material into said chamber, four lateral pistons slidably mounted in said frame for movement toward and away from said chamber in a common plane at right angles to each other for molding the outer side walls of an article, a transfer piston slidably mounted in said frame for movement into and out of said chamber at right angles to said plane for molding the outer bottom surface of said article, said frame having an aperture opposite said transfer piston for receiving a removable molding insert therein, said removable molding insert having a hollow rigid body the interior of which corresponds to the outer surface of the sides of said article, an insert piston slidably mounted in said insert for movement into and out of said chamber opposite said transfer piston, said insert piston having an end surface opposite said transfer piston for defining the inner bottom surface of said article and side surfaces for defining the internal sides of said article, means for moving said insert piston into said chamber for molding the bottom of said container between said insert pistons and said single piston, means for moving said lateral pistons toward said insert piston when it is disposed in said chamber to mold the sides of said article therebetween and means for moving said insert piston and said transfer piston to transfer said article from said chamber into said molding insert for removal from the press with said insert.

2. A molding press according to claim 1 wherein a plurality of identical inserts are provided, each removable insert having handling means for moving said insert into and out of operative engagement with said frame and for enabling a rotation of said insert prior to depositing said insert on an evacuation conveyor provided with a supporting face which has the same shape as the outer face of the article bottom.

3. A molding press according to claim 1 further comprising sleeve means fixed inside said removable insert, said sleeve means having a same thickness as the side walls of the article to be molded and having an end surface for defining the profile of the edges of the side walls of the loaded article.

4. A molding press according to claim 1 further comprising stop means provided between the body of said insert and said insert piston to limit in both directions the amplitude of the sliding movement of said piston within said insert body.

5. A molding press according to claim 1 further comprising latching lugs secured to opposite sides of each insert for cooperation with latches on a delivery conveyor in order to maintain the molded article compressed by the weight of the insert and the latching action.

6. A molding press according to claim 1 wherein said transfer piston is provided with recess means along opposite edges thereof to define a lateral space within which the molding material forms a wall provisionally located under the bottom of said article to be molded, said provisional wall being crushed on the delivery conveyor by the insert weight to define lateral projections disposed in the same plane as the bottom of said molded article. 

1. A molding press for the fabrication of agglomerated wood particles such as packing boxes for the transport of fruits and vegetables comprising a frame having a central molding chamber, feed means for feeding a molding material into said chamber, four lateral pistons slidably mounted in said frame for movement toward and away from said chamber in a common plane at right angles to each other for molding the outer side walls of an article, a transfer piston slidably mounted in said frame for movement into and out of said chamber at right angles to said plane for molding the outer bottom surface of said article, said frame having an aperture opposite said transfer piston for receiving a removable molding insert Therein, said removable molding insert having a hollow rigid body the interior of which corresponds to the outer surface of the sides of said article, an insert piston slidably mounted in said insert for movement into and out of said chamber opposite said transfer piston, said insert piston having an end surface opposite said transfer piston for defining the inner bottom surface of said article and side surfaces for defining the internal sides of said article, means for moving said insert piston into said chamber for molding the bottom of said container between said insert pistons and said single piston, means for moving said lateral pistons toward said insert piston when it is disposed in said chamber to mold the sides of said article therebetween and means for moving said insert piston and said transfer piston to transfer said article from said chamber into said molding insert for removal from the press with said insert.
 2. A molding press according to claim 1 wherein a plurality of identical inserts are provided, each removable insert having handling means for moving said insert into and out of operative engagement with said frame and for enabling a 90* rotation of said insert prior to depositing said insert on an evacuation conveyor provided with a supporting face which has the same shape as the outer face of the article bottom.
 3. A molding press according to claim 1 further comprising sleeve means fixed inside said removable insert, said sleeve means having a same thickness as the side walls of the article to be molded and having an end surface for defining the profile of the edges of the side walls of the loaded article.
 4. A molding press according to claim 1 further comprising stop means provided between the body of said insert and said insert piston to limit in both directions the amplitude of the sliding movement of said piston within said insert body.
 5. A molding press according to claim 1 further comprising latching lugs secured to opposite sides of each insert for cooperation with latches on a delivery conveyor in order to maintain the molded article compressed by the weight of the insert and the latching action.
 6. A molding press according to claim 1 wherein said transfer piston is provided with recess means along opposite edges thereof to define a lateral space within which the molding material forms a wall provisionally located under the bottom of said article to be molded, said provisional wall being crushed on the delivery conveyor by the insert weight to define lateral projections disposed in the same plane as the bottom of said molded article. 